Dirichlet inverse of the gcd-sum function (A018804).

Terms

a(0) =1a(1) =-3a(2) =-5a(3) =1a(4) =-9a(5) =15a(6) =-13a(7) =1a(8) =4a(9) =27a(10) =-21a(11) =-5a(12) =-25a(13) =39a(14) =45a(15) =1a(16) =-33a(17) =-12a(18) =-37a(19) =-9a(20) =65a(21) =63a(22) =-45a(23) =-5a(24) =16a(25) =75a(26) =4a(27) =-13a(28) =-57a(29) =-135